1. Field of the Invention
The present invention relates to a film forming method of spraying an ultrafine particle material jetted from a nozzle onto an object to form a film on the object.
2. Description of the Related Art
Such a film forming technology includes the steps of aerosolizing, with an inactive gas or the like, ultrafine particles made of a ceramic material or a metal material and having particle diameters of 100 μm or smaller to form an ultrafine particle material, and spraying this ultrafine particle material onto an object to deposit a film on the object, and this film formation technology is broadly known as an aerosol deposition method (see e.g. Patent Document 1 described below). In the film forming method disclosed in Patent Document 1, there has been suggested a film forming method which can form a film including sufficiently joined ultrafine particles therein, and having a dense structure, a smooth surface and a uniform density. Specifically, the ultrafine particle material is obliquely sprayed onto a flat surface constituting the object. When the ultrafine particle material is obliquely sprayed in this manner, a high-quality film can be formed.
The film forming method disclosed in Patent Document 1 is a remarkably effective technology in a case where surfaces constituting the object are only flat surfaces, but the technology needs to be further contrived in a case where the surfaces constituting the object include curved surfaces. Specifically, the method is contrived so that a jet angle of the ultrafine particle material keeps to be constant even on the curved surfaces. For example, a technology disclosed in Patent Document 2 described below has been suggested.
In a film forming method disclosed in Patent Document 2, a film is formed on a curved surface constituting an object having a cylindrical shape. An ultrafine particle material is sprayed on the curved surface which is an outer periphery of the cylindrical object, while rotating the cylindrical object around a central axis of the cylindrical object. More specifically, the ultrafine particle material is sprayed on the cylindrical object while rotating the object, and ultrafine particles in the ultrafine particle material reflected by the curved outer peripheral surface of the cylindrical object are allowed to secondarily collide with the surface, to form a uniform film.
Moreover, a film forming method disclosed in Patent Document 3 described below has been suggested as one of film forming methods in a case where the curved surface is formed in part of the outer periphery of the object. In the film forming method disclosed in Patent Document 3, a nozzle for exclusive use having an opening with a width substantially equal to that of the curved surface formed in part of the outer periphery of the object is used, to form a highly dense film on the curved surface.